The project encompasses two distinct long-range goals. First we intend to further elucidate the role of 16S ribosomal RNA in the process of 30S ribosome self-assembly. We have previously shown that the conformation of the 16S molecule can greatly affect its biological activity. For example, we found that in one conformation protein S7 can bind independently and specifically whereas protein S9 cannot. However, in a different RNA conformation induced by protein S7, protein S9 can independently associate with specific sites on the RNA. In related experiments, we have found that protein S19 can specifically bind to a complex of 16S RNA and protein S9. We plan to expand this investigation to other pairs of protein which we suspect may reveal similar relationships. Our second objective is to develop methods which will produce fragments of specific ribosomal proteins which retain partial function in the assembly process for the 30S ribosome. This, we believe, should permit us to develop a detailed understanding of the role played by specific regions of each protein in the self-assembly reaction. Thus far we have concentrated our efforts on protein S4.